The challenge on the ground…

Special Focus: Airports

The travel sector has been hit hard by the pandemic crisis and airports have a difficult challenge to ‘keep the lights on’ even though travel has dropped off a cliff. Andy Waring, Business Development Manager at Pearlstone discusses the unique challenges that face airport managers today...

We have all seen and marvelled at the notion that airports never sleep. If you stand still for long enough you will witness people from all walks of life come and go at all hours of the day. You may not see it first-hand, but you know that behind the scenes goods are also seamlessly moving from one corner of the world to another. These are truly amazing places. But what happens to an airport in a pandemic?

Stage 1 - The initial weeks and months look bleak for an airport that was once bustling, full of motion. The very thing that made it so spectacular is now the reason that people keep away. The transportation of people, be it personal or commercial, halts overnight. Entire countries and continents decide to close borders to protect citizens from an invisible threat. The volume of goods moving between regions takes a significant nosedive as well as business halt all non-essential purchases in favour of cash in the bank. At this stage the airport is a ghost town.

Stage 2 - The uncertainty subsides and people that were once locked up, in fear of outsiders and packages arriving in the mail emerge. Small signs of life return to the airport. Essential travel returns with strict guidelines. Social travel returns in a limited fashion with the construction of special airbridges, allowing people to travel for pleasure (again with strict guidelines) without the need for self-isolation. There are even whispers and hopes of a vaccine.

Stage 3 – The long journey back to normal. Those that were once whispers come to reality. As a vaccine is rolled out, consumer health concerns fade. A global recession is now the barrier to an expedited return to what was once considered ‘normal’.

Of course, this is hugely simplistic, but it does highlight the significant challenge facing airport managers. They need to find a new normal, with limited operations and spaces open to accommodate the reduced numbers. The reality being any of the above stages could last for months and even years so short-term fixes won’t work.

Energy will quickly become a focus area to mitigate expenditure. Further analysis of the building load profile will narrow the cross hairs on Heating, Ventilation and Cooling (HVAC). An airport is typically an arrangement of complex buildings each with different environment zones. A mid-sized UK airport, recently audited by Pearlstone, included the following HVAC technology: a Low Temperature Hot Water (LTWH) boiler system, 3 air-cooled water chillers, a set of 3 circulating pumps, fan coil units, supply and extractor fans.

In this example, air handling units are used to provide tempered fresh air to the main areas of the buildings. The fresh air is heated or cooled at the air handling units to a modulating setpoint temperature depending on outside air conditions. Air is distributed to the space of each building from fan coil units located throughout the facility.

Pearlstone created a comprehensive (pre-covid) load-shed strategy so that during each Automated Demand Response (ADR) event the equipment would respond accordingly:

  • Increase chilled water temperature set point by an agreed amount (subject to tolerances of the building) for the duration of the ADR event. Upon return to Normal status, release the equipment to standard control.
  • Turn down fan coil units in each zone during an ADR event. Establish two control groups to duty cycle for the duration of the ADR event. Upon return to Normal status, release the equipment to standard control.
  • Reduce chilled water pump with Variable Speed Drive (VSD) upon a triggered load shed event for the duration of the ADR event.
  • Reduce the VSD controlling extractor fan by an agreed value for the duration of the ADR event.

In this case, the strategy would result in a load reduction of 43% per event for this type of airport. This is typical turn-down event where the operation of the building would not be affected, and the occupants wouldn’t feel the effects of this load shed. This was a significant cost saving back then. Now, transport us back to today, and given the pressure that airport managers have, this cost saving would be snapped up faster than you can say ‘Job Retention Scheme’. Add on top of this the additional revenue the airport would receive from National Grid as part of their STOR balancing service to keep the electricity network running smoothly; this makes a very compelling case.

There is obviously a lot more to consider in today’s environment. While the above load-shed strategy is still true today, it cannot be applied as deep and as long as a CFOs would like. Airport managers have a strategic operational plan to execute with many moving parts. The pressure is mounting as the crisis endures, and it would not be unrealistic to assume that the CFO is chairing daily zoom meetings to identify even marginal (2-5%) gains in this environment. But asking the question about how to reduce energy consumption in a strategic way is the first step.

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